Re: Waterski speed
I like to go about 16-17 on knee board, 22 on 2 skiis, maybe 26-27 on slalom and 35 barefoot. Beginners on 2 skiis I'd say minimum is about 20mph for an adult, 16 for a kid.
Everyone is different and skiis are different so you just have to try it and see. I can tell the correct speed from the drivers seat by how deep they are in the water or if they start bouncing.